Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * This is a module which is used for logging packets. | |
3 | */ | |
4 | ||
5 | /* (C) 1999-2001 Paul `Rusty' Russell | |
6 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify | |
9 | * it under the terms of the GNU General Public License version 2 as | |
10 | * published by the Free Software Foundation. | |
11 | */ | |
12 | ||
13 | #include <linux/module.h> | |
14 | #include <linux/spinlock.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/ip.h> | |
17 | #include <net/icmp.h> | |
18 | #include <net/udp.h> | |
19 | #include <net/tcp.h> | |
20 | #include <net/route.h> | |
21 | ||
22 | #include <linux/netfilter.h> | |
23 | #include <linux/netfilter_ipv4/ip_tables.h> | |
24 | #include <linux/netfilter_ipv4/ipt_LOG.h> | |
25 | ||
26 | MODULE_LICENSE("GPL"); | |
27 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
28 | MODULE_DESCRIPTION("iptables syslog logging module"); | |
29 | ||
30 | static unsigned int nflog = 1; | |
31 | module_param(nflog, int, 0400); | |
32 | MODULE_PARM_DESC(nflog, "register as internal netfilter logging module"); | |
33 | ||
34 | #if 0 | |
35 | #define DEBUGP printk | |
36 | #else | |
37 | #define DEBUGP(format, args...) | |
38 | #endif | |
39 | ||
40 | /* Use lock to serialize, so printks don't overlap */ | |
41 | static DEFINE_SPINLOCK(log_lock); | |
42 | ||
43 | /* One level of recursion won't kill us */ | |
44 | static void dump_packet(const struct ipt_log_info *info, | |
45 | const struct sk_buff *skb, | |
46 | unsigned int iphoff) | |
47 | { | |
48 | struct iphdr _iph, *ih; | |
49 | ||
50 | ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph); | |
51 | if (ih == NULL) { | |
52 | printk("TRUNCATED"); | |
53 | return; | |
54 | } | |
55 | ||
56 | /* Important fields: | |
57 | * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */ | |
58 | /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */ | |
59 | printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ", | |
60 | NIPQUAD(ih->saddr), NIPQUAD(ih->daddr)); | |
61 | ||
62 | /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */ | |
63 | printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ", | |
64 | ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK, | |
65 | ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id)); | |
66 | ||
67 | /* Max length: 6 "CE DF MF " */ | |
68 | if (ntohs(ih->frag_off) & IP_CE) | |
69 | printk("CE "); | |
70 | if (ntohs(ih->frag_off) & IP_DF) | |
71 | printk("DF "); | |
72 | if (ntohs(ih->frag_off) & IP_MF) | |
73 | printk("MF "); | |
74 | ||
75 | /* Max length: 11 "FRAG:65535 " */ | |
76 | if (ntohs(ih->frag_off) & IP_OFFSET) | |
77 | printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET); | |
78 | ||
79 | if ((info->logflags & IPT_LOG_IPOPT) | |
80 | && ih->ihl * 4 > sizeof(struct iphdr)) { | |
81 | unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op; | |
82 | unsigned int i, optsize; | |
83 | ||
84 | optsize = ih->ihl * 4 - sizeof(struct iphdr); | |
85 | op = skb_header_pointer(skb, iphoff+sizeof(_iph), | |
86 | optsize, _opt); | |
87 | if (op == NULL) { | |
88 | printk("TRUNCATED"); | |
89 | return; | |
90 | } | |
91 | ||
92 | /* Max length: 127 "OPT (" 15*4*2chars ") " */ | |
93 | printk("OPT ("); | |
94 | for (i = 0; i < optsize; i++) | |
95 | printk("%02X", op[i]); | |
96 | printk(") "); | |
97 | } | |
98 | ||
99 | switch (ih->protocol) { | |
100 | case IPPROTO_TCP: { | |
101 | struct tcphdr _tcph, *th; | |
102 | ||
103 | /* Max length: 10 "PROTO=TCP " */ | |
104 | printk("PROTO=TCP "); | |
105 | ||
106 | if (ntohs(ih->frag_off) & IP_OFFSET) | |
107 | break; | |
108 | ||
109 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ | |
110 | th = skb_header_pointer(skb, iphoff + ih->ihl * 4, | |
111 | sizeof(_tcph), &_tcph); | |
112 | if (th == NULL) { | |
113 | printk("INCOMPLETE [%u bytes] ", | |
114 | skb->len - iphoff - ih->ihl*4); | |
115 | break; | |
116 | } | |
117 | ||
118 | /* Max length: 20 "SPT=65535 DPT=65535 " */ | |
119 | printk("SPT=%u DPT=%u ", | |
120 | ntohs(th->source), ntohs(th->dest)); | |
121 | /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */ | |
122 | if (info->logflags & IPT_LOG_TCPSEQ) | |
123 | printk("SEQ=%u ACK=%u ", | |
124 | ntohl(th->seq), ntohl(th->ack_seq)); | |
125 | /* Max length: 13 "WINDOW=65535 " */ | |
126 | printk("WINDOW=%u ", ntohs(th->window)); | |
127 | /* Max length: 9 "RES=0x3F " */ | |
128 | printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22)); | |
129 | /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */ | |
130 | if (th->cwr) | |
131 | printk("CWR "); | |
132 | if (th->ece) | |
133 | printk("ECE "); | |
134 | if (th->urg) | |
135 | printk("URG "); | |
136 | if (th->ack) | |
137 | printk("ACK "); | |
138 | if (th->psh) | |
139 | printk("PSH "); | |
140 | if (th->rst) | |
141 | printk("RST "); | |
142 | if (th->syn) | |
143 | printk("SYN "); | |
144 | if (th->fin) | |
145 | printk("FIN "); | |
146 | /* Max length: 11 "URGP=65535 " */ | |
147 | printk("URGP=%u ", ntohs(th->urg_ptr)); | |
148 | ||
149 | if ((info->logflags & IPT_LOG_TCPOPT) | |
150 | && th->doff * 4 > sizeof(struct tcphdr)) { | |
151 | unsigned char _opt[4 * 15 - sizeof(struct tcphdr)]; | |
152 | unsigned char *op; | |
153 | unsigned int i, optsize; | |
154 | ||
155 | optsize = th->doff * 4 - sizeof(struct tcphdr); | |
156 | op = skb_header_pointer(skb, | |
157 | iphoff+ih->ihl*4+sizeof(_tcph), | |
158 | optsize, _opt); | |
159 | if (op == NULL) { | |
160 | printk("TRUNCATED"); | |
161 | return; | |
162 | } | |
163 | ||
164 | /* Max length: 127 "OPT (" 15*4*2chars ") " */ | |
165 | printk("OPT ("); | |
166 | for (i = 0; i < optsize; i++) | |
167 | printk("%02X", op[i]); | |
168 | printk(") "); | |
169 | } | |
170 | break; | |
171 | } | |
172 | case IPPROTO_UDP: { | |
173 | struct udphdr _udph, *uh; | |
174 | ||
175 | /* Max length: 10 "PROTO=UDP " */ | |
176 | printk("PROTO=UDP "); | |
177 | ||
178 | if (ntohs(ih->frag_off) & IP_OFFSET) | |
179 | break; | |
180 | ||
181 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ | |
182 | uh = skb_header_pointer(skb, iphoff+ih->ihl*4, | |
183 | sizeof(_udph), &_udph); | |
184 | if (uh == NULL) { | |
185 | printk("INCOMPLETE [%u bytes] ", | |
186 | skb->len - iphoff - ih->ihl*4); | |
187 | break; | |
188 | } | |
189 | ||
190 | /* Max length: 20 "SPT=65535 DPT=65535 " */ | |
191 | printk("SPT=%u DPT=%u LEN=%u ", | |
192 | ntohs(uh->source), ntohs(uh->dest), | |
193 | ntohs(uh->len)); | |
194 | break; | |
195 | } | |
196 | case IPPROTO_ICMP: { | |
197 | struct icmphdr _icmph, *ich; | |
198 | static size_t required_len[NR_ICMP_TYPES+1] | |
199 | = { [ICMP_ECHOREPLY] = 4, | |
200 | [ICMP_DEST_UNREACH] | |
201 | = 8 + sizeof(struct iphdr), | |
202 | [ICMP_SOURCE_QUENCH] | |
203 | = 8 + sizeof(struct iphdr), | |
204 | [ICMP_REDIRECT] | |
205 | = 8 + sizeof(struct iphdr), | |
206 | [ICMP_ECHO] = 4, | |
207 | [ICMP_TIME_EXCEEDED] | |
208 | = 8 + sizeof(struct iphdr), | |
209 | [ICMP_PARAMETERPROB] | |
210 | = 8 + sizeof(struct iphdr), | |
211 | [ICMP_TIMESTAMP] = 20, | |
212 | [ICMP_TIMESTAMPREPLY] = 20, | |
213 | [ICMP_ADDRESS] = 12, | |
214 | [ICMP_ADDRESSREPLY] = 12 }; | |
215 | ||
216 | /* Max length: 11 "PROTO=ICMP " */ | |
217 | printk("PROTO=ICMP "); | |
218 | ||
219 | if (ntohs(ih->frag_off) & IP_OFFSET) | |
220 | break; | |
221 | ||
222 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ | |
223 | ich = skb_header_pointer(skb, iphoff + ih->ihl * 4, | |
224 | sizeof(_icmph), &_icmph); | |
225 | if (ich == NULL) { | |
226 | printk("INCOMPLETE [%u bytes] ", | |
227 | skb->len - iphoff - ih->ihl*4); | |
228 | break; | |
229 | } | |
230 | ||
231 | /* Max length: 18 "TYPE=255 CODE=255 " */ | |
232 | printk("TYPE=%u CODE=%u ", ich->type, ich->code); | |
233 | ||
234 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ | |
235 | if (ich->type <= NR_ICMP_TYPES | |
236 | && required_len[ich->type] | |
237 | && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) { | |
238 | printk("INCOMPLETE [%u bytes] ", | |
239 | skb->len - iphoff - ih->ihl*4); | |
240 | break; | |
241 | } | |
242 | ||
243 | switch (ich->type) { | |
244 | case ICMP_ECHOREPLY: | |
245 | case ICMP_ECHO: | |
246 | /* Max length: 19 "ID=65535 SEQ=65535 " */ | |
247 | printk("ID=%u SEQ=%u ", | |
248 | ntohs(ich->un.echo.id), | |
249 | ntohs(ich->un.echo.sequence)); | |
250 | break; | |
251 | ||
252 | case ICMP_PARAMETERPROB: | |
253 | /* Max length: 14 "PARAMETER=255 " */ | |
254 | printk("PARAMETER=%u ", | |
255 | ntohl(ich->un.gateway) >> 24); | |
256 | break; | |
257 | case ICMP_REDIRECT: | |
258 | /* Max length: 24 "GATEWAY=255.255.255.255 " */ | |
259 | printk("GATEWAY=%u.%u.%u.%u ", | |
260 | NIPQUAD(ich->un.gateway)); | |
261 | /* Fall through */ | |
262 | case ICMP_DEST_UNREACH: | |
263 | case ICMP_SOURCE_QUENCH: | |
264 | case ICMP_TIME_EXCEEDED: | |
265 | /* Max length: 3+maxlen */ | |
266 | if (!iphoff) { /* Only recurse once. */ | |
267 | printk("["); | |
268 | dump_packet(info, skb, | |
269 | iphoff + ih->ihl*4+sizeof(_icmph)); | |
270 | printk("] "); | |
271 | } | |
272 | ||
273 | /* Max length: 10 "MTU=65535 " */ | |
274 | if (ich->type == ICMP_DEST_UNREACH | |
275 | && ich->code == ICMP_FRAG_NEEDED) | |
276 | printk("MTU=%u ", ntohs(ich->un.frag.mtu)); | |
277 | } | |
278 | break; | |
279 | } | |
280 | /* Max Length */ | |
281 | case IPPROTO_AH: { | |
282 | struct ip_auth_hdr _ahdr, *ah; | |
283 | ||
284 | if (ntohs(ih->frag_off) & IP_OFFSET) | |
285 | break; | |
286 | ||
287 | /* Max length: 9 "PROTO=AH " */ | |
288 | printk("PROTO=AH "); | |
289 | ||
290 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ | |
291 | ah = skb_header_pointer(skb, iphoff+ih->ihl*4, | |
292 | sizeof(_ahdr), &_ahdr); | |
293 | if (ah == NULL) { | |
294 | printk("INCOMPLETE [%u bytes] ", | |
295 | skb->len - iphoff - ih->ihl*4); | |
296 | break; | |
297 | } | |
298 | ||
299 | /* Length: 15 "SPI=0xF1234567 " */ | |
300 | printk("SPI=0x%x ", ntohl(ah->spi)); | |
301 | break; | |
302 | } | |
303 | case IPPROTO_ESP: { | |
304 | struct ip_esp_hdr _esph, *eh; | |
305 | ||
306 | /* Max length: 10 "PROTO=ESP " */ | |
307 | printk("PROTO=ESP "); | |
308 | ||
309 | if (ntohs(ih->frag_off) & IP_OFFSET) | |
310 | break; | |
311 | ||
312 | /* Max length: 25 "INCOMPLETE [65535 bytes] " */ | |
313 | eh = skb_header_pointer(skb, iphoff+ih->ihl*4, | |
314 | sizeof(_esph), &_esph); | |
315 | if (eh == NULL) { | |
316 | printk("INCOMPLETE [%u bytes] ", | |
317 | skb->len - iphoff - ih->ihl*4); | |
318 | break; | |
319 | } | |
320 | ||
321 | /* Length: 15 "SPI=0xF1234567 " */ | |
322 | printk("SPI=0x%x ", ntohl(eh->spi)); | |
323 | break; | |
324 | } | |
325 | /* Max length: 10 "PROTO 255 " */ | |
326 | default: | |
327 | printk("PROTO=%u ", ih->protocol); | |
328 | } | |
329 | ||
330 | /* Max length: 15 "UID=4294967295 " */ | |
331 | if ((info->logflags & IPT_LOG_UID) && !iphoff && skb->sk) { | |
332 | read_lock_bh(&skb->sk->sk_callback_lock); | |
333 | if (skb->sk->sk_socket && skb->sk->sk_socket->file) | |
334 | printk("UID=%u ", skb->sk->sk_socket->file->f_uid); | |
335 | read_unlock_bh(&skb->sk->sk_callback_lock); | |
336 | } | |
337 | ||
338 | /* Proto Max log string length */ | |
339 | /* IP: 40+46+6+11+127 = 230 */ | |
340 | /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */ | |
341 | /* UDP: 10+max(25,20) = 35 */ | |
342 | /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */ | |
343 | /* ESP: 10+max(25)+15 = 50 */ | |
344 | /* AH: 9+max(25)+15 = 49 */ | |
345 | /* unknown: 10 */ | |
346 | ||
347 | /* (ICMP allows recursion one level deep) */ | |
348 | /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */ | |
349 | /* maxlen = 230+ 91 + 230 + 252 = 803 */ | |
350 | } | |
351 | ||
352 | static void | |
353 | ipt_log_packet(unsigned int hooknum, | |
354 | const struct sk_buff *skb, | |
355 | const struct net_device *in, | |
356 | const struct net_device *out, | |
357 | const struct ipt_log_info *loginfo, | |
358 | const char *level_string, | |
359 | const char *prefix) | |
360 | { | |
361 | spin_lock_bh(&log_lock); | |
362 | printk(level_string); | |
363 | printk("%sIN=%s OUT=%s ", | |
364 | prefix == NULL ? loginfo->prefix : prefix, | |
365 | in ? in->name : "", | |
366 | out ? out->name : ""); | |
367 | #ifdef CONFIG_BRIDGE_NETFILTER | |
368 | if (skb->nf_bridge) { | |
369 | struct net_device *physindev = skb->nf_bridge->physindev; | |
370 | struct net_device *physoutdev = skb->nf_bridge->physoutdev; | |
371 | ||
372 | if (physindev && in != physindev) | |
373 | printk("PHYSIN=%s ", physindev->name); | |
374 | if (physoutdev && out != physoutdev) | |
375 | printk("PHYSOUT=%s ", physoutdev->name); | |
376 | } | |
377 | #endif | |
378 | ||
379 | if (in && !out) { | |
380 | /* MAC logging for input chain only. */ | |
381 | printk("MAC="); | |
382 | if (skb->dev && skb->dev->hard_header_len | |
383 | && skb->mac.raw != (void*)skb->nh.iph) { | |
384 | int i; | |
385 | unsigned char *p = skb->mac.raw; | |
386 | for (i = 0; i < skb->dev->hard_header_len; i++,p++) | |
387 | printk("%02x%c", *p, | |
388 | i==skb->dev->hard_header_len - 1 | |
389 | ? ' ':':'); | |
390 | } else | |
391 | printk(" "); | |
392 | } | |
393 | ||
394 | dump_packet(loginfo, skb, 0); | |
395 | printk("\n"); | |
396 | spin_unlock_bh(&log_lock); | |
397 | } | |
398 | ||
399 | static unsigned int | |
400 | ipt_log_target(struct sk_buff **pskb, | |
401 | const struct net_device *in, | |
402 | const struct net_device *out, | |
403 | unsigned int hooknum, | |
404 | const void *targinfo, | |
405 | void *userinfo) | |
406 | { | |
407 | const struct ipt_log_info *loginfo = targinfo; | |
408 | char level_string[4] = "< >"; | |
409 | ||
410 | level_string[1] = '0' + (loginfo->level % 8); | |
411 | ipt_log_packet(hooknum, *pskb, in, out, loginfo, level_string, NULL); | |
412 | ||
413 | return IPT_CONTINUE; | |
414 | } | |
415 | ||
416 | static void | |
417 | ipt_logfn(unsigned int hooknum, | |
418 | const struct sk_buff *skb, | |
419 | const struct net_device *in, | |
420 | const struct net_device *out, | |
421 | const char *prefix) | |
422 | { | |
423 | struct ipt_log_info loginfo = { | |
424 | .level = 0, | |
425 | .logflags = IPT_LOG_MASK, | |
426 | .prefix = "" | |
427 | }; | |
428 | ||
429 | ipt_log_packet(hooknum, skb, in, out, &loginfo, KERN_WARNING, prefix); | |
430 | } | |
431 | ||
432 | static int ipt_log_checkentry(const char *tablename, | |
433 | const struct ipt_entry *e, | |
434 | void *targinfo, | |
435 | unsigned int targinfosize, | |
436 | unsigned int hook_mask) | |
437 | { | |
438 | const struct ipt_log_info *loginfo = targinfo; | |
439 | ||
440 | if (targinfosize != IPT_ALIGN(sizeof(struct ipt_log_info))) { | |
441 | DEBUGP("LOG: targinfosize %u != %u\n", | |
442 | targinfosize, IPT_ALIGN(sizeof(struct ipt_log_info))); | |
443 | return 0; | |
444 | } | |
445 | ||
446 | if (loginfo->level >= 8) { | |
447 | DEBUGP("LOG: level %u >= 8\n", loginfo->level); | |
448 | return 0; | |
449 | } | |
450 | ||
451 | if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') { | |
452 | DEBUGP("LOG: prefix term %i\n", | |
453 | loginfo->prefix[sizeof(loginfo->prefix)-1]); | |
454 | return 0; | |
455 | } | |
456 | ||
457 | return 1; | |
458 | } | |
459 | ||
460 | static struct ipt_target ipt_log_reg = { | |
461 | .name = "LOG", | |
462 | .target = ipt_log_target, | |
463 | .checkentry = ipt_log_checkentry, | |
464 | .me = THIS_MODULE, | |
465 | }; | |
466 | ||
467 | static int __init init(void) | |
468 | { | |
469 | if (ipt_register_target(&ipt_log_reg)) | |
470 | return -EINVAL; | |
471 | if (nflog) | |
472 | nf_log_register(PF_INET, &ipt_logfn); | |
473 | ||
474 | return 0; | |
475 | } | |
476 | ||
477 | static void __exit fini(void) | |
478 | { | |
479 | if (nflog) | |
480 | nf_log_unregister(PF_INET, &ipt_logfn); | |
481 | ipt_unregister_target(&ipt_log_reg); | |
482 | } | |
483 | ||
484 | module_init(init); | |
485 | module_exit(fini); |